The present invention relates to stabilizing jacks for recreational vehicles adapted to raise the recreational vehicle relative to its suspension to provide stability to the vehicle when parked.
A wide variety of stabilizing jacks have been developed for use in stabilizing recreational vehicles, trailers and the like when parked by raising the vehicle relative to its suspension system to prevent rocking and swaying of the recreational vehicle as an occupant moves around in the vehicle. For example, U.S. Pat. No. 4,103,869 discloses a stabilizing system utilizing four separate jacks mounted in the corners of the vehicle with each jack having a separate gear motor for extending and retracting the leg of the jack. Raising and lowering of the jacks is controlled by an electronic switching system to selectively raise and lower one jack at a time to stabilize and level the vehicle.
Although stabilizing systems such as that shown in U.S. Pat. No. 4,103,869 do conveniently allow the user to raise and lower all four jacks from one location, the need for a separate motor for each jack leg significantly increases the cost of the stabilizing system. In addition, raising and lowering each jack leg independently makes it difficult to properly stabilize the vehicle. For example, with the leg of one of the rear jacks lowered into contact with the ground, as the leg of the other rear jack is lowered into contact with the ground to the point that it pushes upward on the vehicle body, it also lifts the opposite jack leg slightly off of the ground. Using such a system it is difficult to ever get all four jack legs touching the ground at the same time to provide the desired stability.
U.S. Pat. No. 3,870,276 discloses a stabilizing jack for recreational vehicles having a pair of jack legs which are raised and lowered using a single motor. The jack legs are mounted on a frame such that the legs are simultaneously moved downwardly into a stabilizing position beneath the vehicle with an equal force on both of the legs and such that both of the legs strike the ground before further force is applied to either leg to raise the vehicle, such as when the stabilizer is extended on uneven terrain. However, the usefulness of the stabilizing jack as shown in U.S. Pat. No. 3,870,276 is severely limited because the motor for each set of legs is mounted so as to extend downward from the vehicle. In this position, the motor and the stabilizing jack system are prone to damage during transport of the recreational vehicle because of clearance problems. In addition the configuration of the '276 patent limits the length of the legs such that the system may not be useable with current style coaches or trailers whose frames tend to sit higher off of the ground. The newer generation coaches sit higher off of the ground to accommodate slide out rooms and the like.
There remains a need for a relatively low cost stabilizing system which facilitates stabilizing of recreational vehicles and which may be driven by a motor.